1. Field of the Invention
The invention relates to a system for thermal patterning.
2. Description of the Related Art
Display panels have been developed towards large scale and flexible regimes. In order to achieve fast and precise production, conventional fabrication methods for patterned structures include lithography, laser processing, inkjet printing, and thermal print-heat patterning.
Conventional lithography is beneficial due to the fact that its well-developed. However, fabrication method using lithography is complicated and expensive. Further, CO2 laser processing is advantageous due to the fact that it can be practically used. A pattern is created by several laser-scanning lines such that fine traces are left between the laser-scanning lines. However, production throughput is very slow. Additionally, quality is not easy to control due to unstable laser sources. Meanwhile, inkjet printing is beneficial due to low production costs. Inkjet droplets, however, are not easily applied on some materials. Additionally, pattern quality is unstable due to volatile inkjet droplets and crooked ink trajectory.
U.S. Pat. No. 6,498,679, the entirety of which is hereby incorporated by reference, discloses a fabrication method for patterning phase retardation using CO2 laser heating. Patterns with different phase retardation characteristics are formed by laser scanning line by line. Several laser-scanning lines are composed on a patterned region.
FIG. 1 is a schematic view illustrating a layer-by-layer structure of a conventional micro retarder. Referring to FIG. 1, a phase retarder 14 includes a hatched area 14b and a blank area 14a with different phase retardations in which the hatched area 14b is the area exposed to the infra-red CO2 laser, while the blank area 14a is not processed by the infra-red laser. Typically, the hatched area with zero phase retardation and the blank area with the phase retardation are produced by an alternating heating treatment alternating. Both surfaces of the micro-retarder 14 are covered by the layer of index matching glue and the protection layer 10 and 12, and 16 and 18 laminations, respectively. However, laser-scanning lines that produce the hatched area 14b contain fine traces and bubbles.